With the continuous progress of technologies, wireless communication technologies gradually evolve to 5G (the 5th Generation Mobile Communication). Since coming into the 5G stage, one important aim is to achieve flexible configuration of services including broadband connection service, Internet of Things service, Internet of Vehicles service, broadcast service and so on. Since different services have different requirements for indexes of wireless communication systems (for example, a broadband connection service needs high broadband transmission rate and an Internet of Things service needs more narrowband connections), it is desirable for the wireless communication systems to allocate time-frequency resources more flexibly. For example, as shown in FIG. 1, time-frequency resource blocks of different size are configured flexibly, instead of configuring time-frequency resource blocks of the same size. Under this configuration mechanism, the subcarrier interval also needs to be configured flexibly according to service demands. That is, a variable subcarrier interval, instead of a fixed subcarrier interval, is configured flexibly according to different services. However, at present, a user equipment can only communicate with a base station normally in the case of a fixed subcarrier interval. Therefore, taking into account flexible service configuration as well as communication demands, how to perform communications in the case of a dynamic and variable subcarrier interval needs to be addressed.